Pseudoceros mexicanus Hyman 1953

Pseudoceros mexicanus Hyman, 1953 Pseudoceros mexicanus Hyman, 1953a: 363–364, figs 132–134 (type locality: Puerto Peñasco, Sonora, Mexico). Pseudoceros mexicanus – Brusca 1980: 72, fig. 4.8 (identification keys); 2005: 70, fig. 4.8. (new record from Guaymas, Sonora, Mexico). Distribution Puerto Peñasco, Guaymas, Sonora; Gulf of California, Mexico. Habitat Benthic (under rocks in the low intertidal). Remarks Pseudoceros mexicanus was only partially described by Hyman (1953a), who only characterized the external morphology of the species, since none of the specimens had a developed reproductive system. Pseudoceros mexicanus has an elongated oval body with a blunt posterior end and a brown or dark purple dorsal region, marginal eyes in the anterior region, tentacular eyes and cerebral eyes distributed in circular form, pseudotentacles; pharynx located in the first third of the body with approximately 15 pharyngeal lobes. Brusca (1980) later recorded the species in the Gulf of California, describing a brown to dark purple or reddish-purple coloration, with a reddish orange margin and a dorsal coloration pattern composed of scattered white speckles. We suggest a thorough revision and comparison of the biological material determined by Hyman (1953a) and Brusca (1980) for the area. Additionally, we suggest the collection of topotypic material and a redescription of the species to corroborate if the coloration variants and the coloration pattern are part of an intraspecific variation or indicate the presence of two distinct species.